Infection Prevention & Control Flashcards
What are the stages involved in the chain of infection?
- Pathogenic organism
- Reservoir or source that allows organism to survive and multiply
- Mode of exit from the source
- Mode of transmission from the source to the host
- Portal of entry through which the pathogen can enter the host
- Susceptible (non-immune) host
What is significant about the pathogenic organism involved in the chain of infection?
They must be of sufficient virulence and in adequate numbers to cause disease
What is involved in infection prevention & control (IPC)?
Any activities undertaken with the aim of breaking the chain of infection
By which methods may IPC be acheived?
- Eliminate the pathogenic organism
- remove the source / reservoir
- minimise transmission
- eliminate exit and entry
- reduce susceptibility to infection
What actions can be taken to eliminate the pathogenic organism?
Environmental cleaning & decontamination:
- H2O2 room decontamination
- spillage management
- laundry
Equipment decontamination:
- sterilisation
- disinfection
Antisepsis:
- surgical skin prep
- MRSA decolonisation
Antibiotic prophylaxis:
- perioperative
- post-exposure
What methods can be used to remove the source / reservoir?
- Hand hygiene
- environmental cleaning and decontamination
What steps can be taken to try and minimise transmission?
Hand hygiene
Personal protective equipment (PPE):
- Aprons, gloves and masks
Equipment decontamination:
- surgical instruments
- stethoscopes, blood pressure monitors, USS probes, etc.
Use of disposable equipment:
- syringes, needles, etc.
source and protective isolation
What are the 2 types of bacteria that everyone carries on their hands?
What are the difference in properties of these bacteria?
Resident bacteria:
- deep seated
- difficult to remove
Transient bacteria:
- easily picked up and transferred
- easily removed
- important cause of healthcare associated infections
What are the 5 moments for hand hygiene at the point of care?
- Before patient contact
- Before a septic task
- After body fluid exposure risk
- After patient contact
- After contact with patient surroundings
When should soap and water be used?
When should alcohol gel be used?
Soap & water:
- for visibly soiled hands
- contact with particular infections e.g. C. Difficile, viral gastroenteritis
Alcohol gel:
- suitable for most activities that are likely to be undertaken when visiting clinical areas
What is the definition of decontamination?
A combination of processes that removes or destroys contamination so that infectious agents or other contaminants cannot reach a susceptible site in sufficient quantities to initiate infection, or other harmful response
What are the different decontamination methods?
- Sterilisation
- Disinfection
- Antisepsis
Which method is appropriate / required depends on the situation
What is involved in sterilisation?
When is it used?
This is the complete killing or removal of all types of micro-organisms
bacteria:
- vegetative - endowed with the power or faculty of growth
- spores - C. Tetani, difficile, perfringens
also for viruses, fungi and mycobacteria
What are the 4 sterilisation methods used?
- Heat - moist or dry
- Chemical - gas or liquid
- Filtration
- Ionising radiation - used for single use disposable equipment
How is sterilisation by moist and dry heat acheived?
Moist heat:
- autoclave
- involves delivery of steam under high pressure
- specific pressure and temperature cycles
Dry heat:
- oven
- acheived through controlled temperature cycles
What is meant by “disinfection”?
The removal or destruction of sufficient numbers of potentially harmful micro-organisms to make an item safe to use
What is meant by “antisepsis”?
Disinfection applied to damaged skin or living tissues
this requires a disinfectant with minimal toxicity
How is disinfection acheived?
Almost always by the use of chemical disinfectants
What properties of chemical disinfectants need to be considered?
Effects on microorganisms:
- antimicrobial spectrum
- sporicidality
Chemical properties:
- shelf life, in-use concentration, compatibility with other chemicals
Physical effects:
- corrosiveness
Harmful effects:
- irritant potential and toxicity
What factors need to be considered when deciding which decontamination method to be used?
Risk of infection:
- high, medium or low
Physical properties:
- item
- packaging materials
Decontamination level:
- sterilisation, disinfection (antisepsis), cleaning, disposal
What decontamination method should be used where possible?
Heat
this should be used where possible as it is the least hazardous method
What is chemical disinfection limited to?
- Environmental decontamination - surfaces, spills, etc
- antisepsis
- heat-sensitive items
In general, when should sterilisation, disinfection and cleaning be used as decontamination methods?
Sterilisation:
- items / devices that will enter sterile body areas or break the skin
Disinfection:
- items / devices that will contact mucous membranes or that will be contaminated with body fluids
Cleaning:
- items / devices that only contact intact skin (no body fluids)
For surgical intstrument reprocessing, what is the risk of infection, decontamination level and method?
What physical properties must be considered?
Risk of infection:
- high
Physical properties:
- Metal construction
- paper / cloth packaging
Decontamination level:
- sterilisation
Decontamination method:
- moist heat
For a flexible endoscope, what is the risk of infection, decontamination level and decontamination method?
What are the physical properties to consider?
Risk of infection:
- high
Physical properties:
- metal / plastic construction
- fragile, sensitive parts
Decontamination level:
- ”high level” decontamination
Decontamination method:
- chemical
for a syringe needle, what is the risk of infection and decontamination level and method?
What physical properties need to be considered?
Risk of infection:
- high
Physical properties:
- plastic / metal construction
- paper packaging
Decontamination level:
- sterilisation
Decontamination method:
- y-irradiation pre-use
- disposal after use
What are the physical properties, decontamination level and method that should be used for a central venous catheter insertion site?
Physical properties:
- living tissue
Decontamination level:
- disinfection (antisepsis)
Decontamination method:
- chemical
- 2% chlorhexidine in 70% isopropyl alcohol
